Michał Wierzchoń

Subjective measures of consciousness in artificial grammar learning task

Consciousness can be measured in various ways, but different measures often yield different conclusions about the extent to which awareness relates to performance. Here, we compare five different subjective measures of awareness in the context of an artificial grammar learning task. Participants (N=217) expressed their subjective awareness of rules using one of five different scales: confidence ratings (CRs), post-decision wagering (PDW), feeling of warmth (FOW), rule awareness (RAS), and continuous scale (SDS). All scales were equally sensitive to conscious knowledge. PDW, however, was affected by risk aversion, and both RAS and SDS applied different minimal criteria for rule awareness. CR seems to capture the largest range of consciousness, but failed to indicate unconscious knowledge with the guessing criterion. We close by discussing the theoretical implications of scale sensitivity and propose that CRs unique features enable (in conjunction with RAS and FOW) a finer assessment of subjective states of awareness.

Different subjective awareness measures demonstrate the influence of visual identification on perceptual awareness ratings

We compare four subjective awareness measures in the context of a visual identification task and investigate quantitative differences in terms of scale use and correlation with task performance. We also analyse the effect of identification task decisions on subsequent subjective reports. Results show that awareness ratings strongly predict accuracy for all scale types, although the type of awareness measure may influence the reported level of perceptual awareness. Surprisingly, the overall relationship between awareness ratings and performance was weaker when participants rated their awareness before providing identification responses. Furthermore, the Perceptual Awareness Scale was most exhaustive only when used after the identification task, whereas confidence ratings were most exhaustive when used before the identification task. We conclude that the type of subjective measure applied may influence the reports on visual awareness. We also propose that identification task decisions may affect subsequent awareness ratings.

Rubber Hand Illusion Reduces Discomfort Caused by Cold Stimulus

There is a growing interest in body-ownership disruptions and their consequences for subjective experiences such as tactile sensations or pain. Here, we investigated the effect of the rubber hand illusion (RHI) on the perceived discomfort caused by cold stimulus applied to the real hand. The results showed reduced discomfort to cold reflected in behavioural and subjective measures. The stronger the illusion, the later the cold temperature became unpleasant and the less intense the experience was rated. We discuss the link between thermoception and body ownership as well as possible theoretical and methodological implications for studies on pain experience under RHI.

But I Was So Sure! Metacognitive Judgments Are Less Accurate Given Prospectively than Retrospectively.

Prospective and retrospective metacognitive judgments have been studied extensively in the field of memory; however, their accuracy has not been systematically compared. Such a comparison is important for studying how metacognitive judgments are formed. Here, we present the results of an experiment aiming to investigate the relation between performance in an anagram task and the accuracy of prospective and retrospective confidence judgments. Participants worked on anagrams and were then asked to respond whether a presented word was the solution. They also rated their confidence, either before or after the response and either before or after seeing the suggested solution. The results showed that although response accuracy always correlated with confidence, this relationship was weaker when metacognitive judgements were given before the response. We discuss the theoretical and methodological implications of this finding for studies on metacognition and consciousness.

Manipulating attentional load in sequence learning through random number generation.

Implicit learning is often assumed to be an effortless process. However, some artificial grammar learning and sequence learning studies using dual tasks seem to suggest that attention is essential for implicit learning to occur. This discrepancy probably results from the specific type of secondary task that is used. Different secondary tasks may engage attentional resources differently and therefore may bias performance on the primary task in different ways. Here, we used a random number generation (RNG) task, which may allow for a closer monitoring of a participant’s engagement in a secondary task than the popular secondary task in sequence learning studies: tone counting (TC). In the first two experiments, we investigated the interference associated with performing RNG concurrently with a serial reaction time (SRT) task. In a third experiment, we compared the effects of RNG and TC. In all three experiments, we directly evaluated participants’ knowledge of the sequence with a subsequent sequence generation task. Sequence learning was consistently observed in all experiments, but was impaired under dual-task conditions. Most importantly, our data suggest that RNG is more demanding and impairs learning to a greater extent than TC. Nevertheless, we failed to observe effects of the secondary task in subsequent sequence generation. Our studies indicate that RNG is a promising task to explore the involvement of attention in the SRT task.

Neuronal Network and Awareness Measures of Post-Decision Wagering Behavior in Detecting Masked Emotional Faces

Awareness can be measured by investigating the patterns of associations between discrimination performance (first-order decisions) and confidence judgments (knowledge). In a typical post-decision wagering (PDW) task, participants judge their performance by wagering on each decision made in a detection task. If participants are aware, they wager advantageously by betting high whenever decisions are correct and low for incorrect decisions. Thus, PDW—like other awareness measures with confidence ratings—quantifies if the knowledge upon which they make their decisions is conscious. The present study proposes a new method of assessing the association between advantageous wagering and awareness in the PDW task with a combination of log-linear (LLM) modeling and neural network simulation to reveal the computational patterns that establish this association. We applied the post-decision wagering measure to a backward masking experiment in which participants made first-order decisions about whether or not a masked emotional face was present, and then used imaginary or real monetary stakes to judge the correctness of their initial decisions. The LLM analysis was then used to examine whether advantageous wagering was aware by testing a hypothesis of partial associations between metacognitive judgments and accuracy of first-order decisions. The LLM outcomes were submitted into a feed-forward neural network. The network served as a general approximator that was trained to learn relationships between input wagers and the output of the corresponding log-linear function. The simulation resulted in a simple network architecture that successfully accounted for wagering behavior. This was a feed-forward network unit consisting of one hidden neuron layer with four inputs and one output. In addition, the study indicated no effect of the monetary incentive cues on wagering strategies, although we observed that only low-wager input weights of the neural network considerably contributed to advantageous wagering.

Shades of Awareness on the Mechanisms Underlying the Quality of Conscious Representations: A Commentary to Fazekas and Overgaard (2018).

Fazekas and Overgaard () present a novel, multidimensional model that explains different ways in which conscious representations can be degraded. Moreover, the authors discuss possible mechanisms that underlie different kinds of degradation, primarily those related to attentional processing. In this letter, we argue that the proposed mechanisms are not sufficient. We propose that (1) attentional mechanisms work differently at various processing stages; and (2) factors that are independent of attentional ones, such as expectation, previous experience, and context, should be accounted for if we are aiming to construct a comprehensive model of conscious visual perception.

Four-Dimensional Graded Consciousness

Both the multidimensional phenomenon and the polysemous notion of consciousness continue to prove resistant to consistent measurement and unambiguous definition. This is hardly surprising, given that there is no agreement even as regards the most fundamental issues they involve. One of the basic disagreements present in the continuing debate about consciousness pertains to its gradational nature. The general aim of this article is to show how consciousness might be graded and multidimensional at the same time. We therefore focus on the question of what it is, exactly, that is or could be graded in cases of consciousness, and how we can measure it. Ultimately, four different gradable aspects of consciousness will be described: quality, abstractness, complexity and usefulness, which belong to four different dimensions, these being understood, respectively, as phenomenal, semantic, physiological, and functional. Consequently, consciousness may be said to vary with respect to phenomenal quality, semantic abstraction, physiological complexity, and functional usefulness. It is hoped that such a four-dimensional approach will help to clarify and justify claims about the hierarchical nature of consciousness. The approach also proves explanatorily advantageous, as it enables us not only to draw attention to certain new and important differences in respect of subjective measures of awareness and to justify how a given creature may be ranked higher in one dimension of consciousness and lower in terms of another, but also allows for innovative explanations of a variety of well-known phenomena (amongst these, the interpretations of blindsight and locked-in syndrome will be briefly outlined here). Moreover, a 4D framework makes possible many predictions and hypotheses that may be experimentally tested (We point out a few such possibilities pertaining to interdimensional dependencies).

The level of subjective visibility at different stages of memory processing

ABSTRACT Recent research suggests that the content of iconic memory (IM) and fragile visual short-term memory could be associated with a similar level of conscious accessibility as working memory (WM). The results of our studies, in which we used a subjective visibility scale in a partial-report change detection paradigm, indicate that it is possible to distinguish separate stages of memory based on both discriminative accuracy and conscious accessibility. The highest scores were associated with IM and the lowest with WM, while somewhere in the middle there was fragile memory. Based on classical assumptions, WM accessibility should be greater than the other two types of memory; however, our study showed that this might not always be the case. We discuss the potential sources of this outcome, of which one may be the task construction, as we only tested items that were directly in the focus of attention.

When a (precise) awareness measure became a (sketchy) introspective report

13 Subjective measures of awareness, such as confidence ratings (CR), post-decision wagering (PDW) or the perceptual 14 awareness scale (PAS) have recently been the object of an intense debate. Different such methods have now been system15 atically compared in several recent studies (see e.g. Dienes & Seth, 2010; Sandberg, Timmermans, Overgaard, & Cleeremans, 16 2010; Wierzchoń, Asanowicz, Paulewicz & Cleeremans, 2012). Each method has its pros and cons, but they all aim to offer 17 reliable quantitative measures of awareness as reported subjectively by participants. Importantly, such methods contrast 18 both with introspective reports, which have been criticized as insensitive and imprecise, and with objective measures, which 19 fail to reflect subjective experience per se. Subjective methods usually quantify awareness reports with a pre-set taxonomy 20 of awareness judgments. 21 To our surprise, in their commentary, Sandberg, Bibby, and Overgaard (2013) question our statement that PAS ‘‘is a 22 4-point verbal scale that attempts to measure the quality of conscious experience directly’’ (Szczepanowski, Traczyk, Wierz23 choń, & Cleeremans, 2013, p. 213) and suggest we used PAS in a different manner than originally intended. The authors claim 24 that the scale should reflect the way participants prefer to report and propose to adjust the scale taxonomy depending on the 25 type of stimuli used in the task rather than use – the 4-point scale each time. Thus, the scale should undergo a new 26 calibration procedure whenever new stimuli are used. Alternatively, to avoid scale recalibration, they propose that amend 27 the procedure so as to incorporate ‘‘(1) a full instruction explaining the meaning of each scale point in detail, (2) a pilot test 28 with a good amount of trials (e.g. 30–50) in which the experimenter interrupts the subject frequently to ask about the use of 29 the individual scale points (e.g. ‘‘I noticed you just reported ‘‘brief glimpse’’ – why did you do that/what did you mean with 30 that/how would you define brief glimpse?’’)’’ (Sandberg et al., 2013, p. 808). 31 In our view, those recommendations, far from solving any measurement issues, would rather substantially burden admin32 istration of the PAS scale, decreasing both its applicability and reliability. We address both points in the following, finding 33 ourselves in the somewhat paradoxical position of having to defend PAS against criticism expressed by its very proponents. 34 First, it is not clear why Sandberg et al. (2013) propose to recalibrate the scale each time a new type of a stimuli are inves35 tigated. To our knowledge, there is no evidence that this is necessary. While the scale indeed originally stemmed from intro36 spective-like experiments in which participants were extensively interviewed about their preferred categories to describe 37 degrees of visual awareness (Ramsøy & Overgaard, 2004), few subsequent studies used this involved procedure. The pilot 38 study itself was replicated a few times with different stimuli (Overgaard, Nielsen, & Fuglsang-Frederiksen, 2004; Overgaard, 39 Rote, Mouridsen, & Ramsøy, 2006), always resulting in the very same taxonomy. All other studies used the 4-point scale. We 40 also found at least two studies for which a pilot study was not reported at all (Sandberg et al., 2010; Sandberg, Bibby, 41 Timmermans, Cleeremans, & Overgaard, 2011). Thus, it seems that PAS has typically been used in the manner we report 42 in our study.